JP6779883B2 - Separator for lead-acid battery, lead-acid battery and manufacturing method thereof - Google Patents

Description

The present invention relates to a separator for a lead storage battery, a lead storage battery, and a method for manufacturing the same.

In recent years, in the automobile industry, an idling stop vehicle (hereinafter referred to as "ISS vehicle") has been developed for the purpose of carbon dioxide regulation measures or fuel efficiency reduction. An ISS vehicle is a vehicle having a control function of suppressing carbon dioxide gas emission by stopping the engine when the vehicle is stopped. Compared to conventional vehicles, the amount of discharge increases in ISS vehicles due to the need to supply electric power to electrical components (lights, etc.) during idling stop and the need to discharge a large current when the engine is restarted. ..

Further, in the ISS vehicle, the charging opportunity is reduced, so that the charging amount is reduced. Therefore, as the cycle elapses, the battery becomes insufficiently charged, and the System of Charge (hereinafter referred to as “SOC”) decreases. Then, in a cycle in which charging is likely to be insufficient, stratification of the electrolytic solution is likely to occur. Stratification of the electrolytic solution means that the sulfate ions generated from the electrode plate during charging descend due to gravity, causing a difference in the concentration of sulfate ions between the upper part and the lower part of the electrolytic solution, and the concentration is high in the lower part and concentrated in the upper part. Is a phenomenon of thinning.

In the ISS cycle, the electrolytic solution is not fully charged, and the electrolytic solution is less likely to be agitated due to subsequent gas generation, so that the electrolytic solution is likely to be stratified. When stratification occurs, the lower part of the electrode plate is exposed to high-concentration sulfuric acid, and lead sulfate accumulates in the active material, which tends to lead to an early life.

Therefore, in order to prevent the stratification of this electrolytic solution, in Patent Document 1 below, a non-woven fabric is interposed between the bag-shaped separator and the negative electrode plate to prevent the sulfate ions eluted from lead sulfate from falling during charging, and electrolysis is performed. It is disclosed to prevent the stratification of the liquid.

Japanese Patent No. 5500315

By the way, in a lead-acid battery, it is desirable to further improve the cycle characteristics (cycle life characteristics) as compared with the conventional case, in addition to suppressing the stratification of the electrolytic solution. Here, when a lead-acid battery is manufactured by using a laminated sheet obtained by laminating a plurality of sheets as a separator for a lead-acid battery, if the constituent members of the lead-acid battery are displaced from each other, chemical conversion cannot be performed. , Lead-acid batteries with excellent cycle characteristics may not be obtained.

The present invention has been made in view of the above circumstances, and is a separator for a lead-acid battery capable of obtaining a lead-acid battery having excellent cycle characteristics while suppressing misalignment of components of the lead-acid battery, and a method for manufacturing the same. The purpose is to provide. Another object of the present invention is to provide a lead storage battery having excellent cycle characteristics and a method for producing the same.

The lead-acid battery separator according to the present invention includes a long first porous sheet, a laminated sheet having a second porous sheet laminated on the first porous sheet, the first porous sheet, and the said. A misalignment prevention portion for fixing the relative positions of the second porous sheets to each other is provided, and the surface of the first porous sheet on the side of the second porous sheet is provided in the lateral direction of the first porous sheet. At least one edge is exposed from the second porous sheet.

By the way, in the technique disclosed in Patent Document 1, when it is difficult to insert the negative electrode plate due to the non-woven fabric breaking when the negative electrode plate is inserted into the bag-shaped separator, or to obtain a bag-shaped separator. When joining by bending, the non-woven fabric may be misaligned at the joint, resulting in poor adhesion. When such poor adhesion occurs, battery performance such as cycle characteristics tends to deteriorate. On the other hand, according to the lead-acid battery separator according to the present invention, the position shift between the sheets is suppressed by fixing the relative positions of the first porous sheet and the second porous sheet, so that the lead-acid battery is configured. It is possible to obtain a lead-acid battery having excellent cycle characteristics while suppressing misalignment of members. That is, according to the separator for a lead-acid battery according to the present invention, it is possible to obtain a lead-acid battery having excellent cycle characteristics while suppressing the misalignment of the constituent members of the lead-acid battery, which is a problem mainly caused during the manufacture of the lead-acid battery. it can. Further, according to the separator for a lead storage battery according to the present invention, a lead storage battery having excellent cycle characteristics can be obtained with good productivity.

A plurality of the misalignment prevention portions may be arranged along the longitudinal direction of the first porous sheet. The misalignment prevention portion may be a heat welding portion, an ultrasonic welding portion, an adhesive, a double-sided tape, or a crimping portion.

The first porous sheet and the second porous sheet may be in contact with each other. The average pore diameter of the second porous sheet is preferably 1 to 200 μm. The second porous sheet may contain at least one selected from the group consisting of organic fibers, glass fibers and pulp. It is preferable that at least one surface of the second porous sheet is hydrophilized. It is preferable that the edge portion of the first porous sheet has a portion where the exposure amount of the first porous sheet in the lateral direction is 2 to 9 mm.

It is preferable that at least one surface of the second porous sheet has at least one selected from the group consisting of a sulfone group, a carboxyl group and a hydroxyl group. In the lead-acid battery separator according to the present invention, the first porous sheet has a first rib and a second rib extending in the longitudinal direction of the first porous sheet, and the second rib is the said. A plurality of the first porous sheets may be arranged at both ends in the lateral direction, and the first ribs may be arranged in a region between the both ends. It is preferable that 10 to 40 of the second ribs are arranged at each of the both ends.

In the lead-acid battery separator according to the present invention, the laminated sheet is bent so that the second porous sheet is located inside, and the edges of the first porous sheet are joined to each other to form an electrode. It may be an embodiment (a negative electrode storage bag for a lead storage battery) in which a space capable of storing the lead storage battery is formed.

In the method for producing a separator for a lead storage battery according to the present invention, the first porous sheet and the second porous sheet are formed so that the edge portion of the first porous sheet is exposed from the second porous sheet. A step of laminating to obtain a separator is provided.

The first embodiment of the lead-acid battery according to the present invention includes the lead-acid battery separator, the positive electrode, and the negative electrode housed in the space of the separator, and the negative electrode and the positive electrode are alternately arranged. There is. Such a lead-acid battery has excellent cycle characteristics and is excellent in productivity.

A second embodiment of the lead storage battery according to the present invention is a lead storage battery including an electric tank, an electrode group and an electrolytic solution housed in the electric tank, and the electrode groups are laminated via a separator. The positive electrode has a positive electrode current collector and a positive electrode material held by the positive electrode current collector, and the negative electrode has a negative electrode current collector and the negative electrode current collector. The separator has a first porous sheet and a second porous sheet having an average pore diameter of 1 to 200 μm, and has at least one of the second porous sheets. The portion is arranged between the negative electrode and the first porous sheet.

The lead-acid battery according to the second embodiment has excellent cycle characteristics because at least a part of the second porous sheet having an average pore diameter of 1 to 200 μm is arranged between the negative electrode and the first porous sheet. Have.

In the lead-acid battery according to the second embodiment, it is preferable that at least one surface of the second porous sheet has at least one selected from the group consisting of a sulfone group, a carboxyl group and a hydroxyl group. In the lead storage battery according to the second embodiment, the first perforated sheet is long and has a first rib and a second rib extending in the longitudinal direction of the first perforated sheet. A plurality of ribs 2 are arranged at both ends of the first porous sheet in the lateral direction, and the first ribs are arranged in a region between both ends. May be good. In the lead storage battery according to the second embodiment, it is preferable that 10 to 40 of the second ribs are arranged at each of the both end portions.

The method for manufacturing a lead-acid battery according to the present invention includes a step of obtaining a lead-acid battery by using the positive electrode, the negative electrode, and the separator.

According to the present invention, it is possible to provide a separator for a lead-acid battery and a method for manufacturing the same, which can obtain a lead-acid battery having excellent cycle characteristics while suppressing misalignment of constituent members of the lead-acid battery. Further, according to the present invention, it is possible to provide a lead storage battery having excellent cycle characteristics and a method for producing the same. Further, according to the present invention, it is possible to achieve both excellent cycle characteristics and other excellent battery performance (charge acceptance performance, etc.). Further, according to the present invention, it is possible to provide a lead storage battery and a method for manufacturing the same, which have extremely little decrease in charge capacity and can be sufficiently satisfied for use in ISS vehicles used in harsh environments.

According to the present invention, it is possible to provide an application of a separator for a lead storage battery to a lead storage battery in a micro-hybrid vehicle. According to the present invention, it is possible to provide an application of a lead storage battery to a micro hybrid vehicle. According to the present invention, it is possible to provide an application of a lead storage battery to an ISS vehicle.

It is sectional drawing which shows an example of the laminated structure of a positive electrode, a negative electrode and a separator. It is a drawing which shows an example of a perforated sheet. It is sectional drawing which shows an example of the laminated structure of a perforated sheet and an electrode. It is a figure which shows an example of the state which accommodates a negative electrode in a bag-shaped separator.

Hereinafter, embodiments of the present invention will be described in detail. Since the specific gravity changes depending on the temperature, it is defined in this specification as the specific gravity converted at 20 ° C. In the present specification, the phrase "the present embodiment" includes the first embodiment and the second embodiment.

<Lead-acid battery>
The lead-acid battery according to the present embodiment includes, for example, an electric tank, an electrode group, an electrolytic solution (sulfuric acid, etc.) and a separator. The electrode group and the electrolytic solution are housed in the electric tank. The electrode group has a plurality of electrodes, for example, a electrode plate group having a plurality of electrode plates (plate-shaped electrodes). The electrode group has a positive electrode (positive electrode plate, etc.) and a negative electrode (negative electrode plate, etc.) facing each other via a separator. As the lead storage battery according to the present embodiment, a liquid lead storage battery is preferable.

The positive electrode and the negative electrode form an electrode group (electrode plate group or the like) by being laminated with a separator, for example. The positive electrode has a current collector (positive electrode current collector) and a positive electrode material held by the current collector. The negative electrode has a current collector (negative electrode current collector) and a negative electrode material held by the current collector. In the present embodiment, the positive electrode material and the negative electrode material are, for example, electrode materials after chemical conversion. When the electrode material is unchemical, the electrode material (unchemical positive electrode material and unchemical negative electrode material) contains raw materials for the electrode active material (positive electrode active material and negative electrode active material) and the like. The current collector constitutes a conductive path for the current from the electrode material. As the basic configuration of the lead-acid battery, the same configuration as that of the conventional lead-acid battery can be used.

The separator has a first porous sheet and a second porous sheet. In a lead-acid battery, at least a part of the second porous sheet is arranged, for example, between the first porous sheet and the negative electrode. The second porous sheet is arranged on the negative electrode side with respect to the first porous sheet, for example. In the present embodiment, the separator has a first porous sheet and a second porous sheet laminated on the first porous sheet so that the surface of the separator facing the negative electrode is composed of the second porous sheet. The laminated sheet can be used as a separator.

The lead-acid battery separator according to the first embodiment includes a long first porous sheet, a laminated sheet having a second porous sheet laminated on the first porous sheet, and the first porous sheet. And a misalignment prevention portion for fixing the relative positions of the second perforated sheet to each other. In the lead-acid battery separator according to the first embodiment, at least one edge of the first porous sheet in the lateral direction on the surface of the first porous sheet on the side of the second porous sheet is the second. Exposed from the perforated sheet. That is, the edge portion of the first porous sheet protrudes more than the second porous sheet in the lateral direction of the first porous sheet, and by joining the overhanging portions in this way, a bag-like shape is formed. A separator can be obtained.

The amount of exposure of the first porous sheet in the lateral direction at the edge of the first porous sheet (the amount of exposure from the second porous sheet. The edge of the first porous sheet in the lateral direction of the first porous sheet. The distance) from the portion to the end portion of the second porous sheet is preferably in the following range. The lower limit of the amount of exposure is 2 mm or more from the viewpoint that when the first porous sheet is formed into a bag shape, the first porous sheets can be easily joined to each other, the joined portion has sufficient strength, and the productivity is excellent. Preferably, 4 mm or more is more preferable, and 5 mm or more is further preferable. The upper limit of the exposure amount is not particularly limited, but from a practical point of view, it is preferably 20 mm or less, more preferably 15 mm or less, still more preferably 10 mm or less. The upper limit of the exposure amount is particularly preferably 9 mm or less from the viewpoint of easily obtaining the stratification suppressing effect. From these viewpoints, the exposure amount is preferably 2 to 20 mm, more preferably 2 to 15 mm, further preferably 2 to 10 mm, particularly preferably 2 to 9 mm, extremely preferably 4 to 9 mm, and very preferably 5 to 9 mm. .. It is preferable that the edge portion of the first porous sheet has a portion (exposed portion) where the exposure amount satisfies the above range. All of the edges may have the amount of exposure.

In the lead-acid battery separator according to the first embodiment, for example, the laminated sheet is bent so that the second porous sheet is located inside, and the edges of the first porous sheet are joined to each other. As a result, a space (electrode storage space) for storing electrodes may be formed (electrode storage bag for lead-acid battery). In this case, by arranging the electrode in the space, it is possible to arrange the second porous sheet between the electrode and the first porous sheet. The electrode may be housed in the space with the electrode and the second porous sheet in contact with each other. For example, in the electrode storage bag, the inner surface of the second porous sheet forms an electrode storage space, and the outer surface of the second porous sheet is in contact with the inner surface of the first porous sheet.

The first perforated sheet may have ribs on one side or both sides. The ribs extend in the longitudinal direction of the first perforated sheet, for example. The first porous sheet has a main rib (first rib) and a mini rib (second rib) extending in the longitudinal direction of the first porous sheet, and the mini rib is in the lateral direction of the first porous sheet. A plurality of main ribs may be arranged at each of both ends, and the main ribs may be arranged in a region between the both ends. When the first perforated sheet has ribs on one surface, for example, the one surface may be located outside the electrode storage bag. The electrode storage bag is, for example, a negative electrode storage bag for a lead storage battery having a space for storing a negative electrode.

The lead storage battery according to the first embodiment includes, for example, a negative electrode storage bag for a lead storage battery, a positive electrode, and a negative electrode stored in the space of the negative electrode storage bag, and the negative electrode and the positive electrode are alternately arranged. It is an arrangement mode. In the lead storage battery according to the second embodiment, the separator has a first porous sheet and a second porous sheet having an average pore diameter of 1 to 200 μm, and at least a part of the second porous sheet is said. This is an embodiment in which the negative electrode is arranged between the negative electrode and the first porous sheet.

Under PSOC, the main components of the negative electrode active material are, for example, spongy lead (metal lead) which is hardly charged and lead sulfate which is negatively charged. Therefore, the negative electrode is mainly negatively charged. This means that the solid phase of the negative electrode active material (including lead sulfate and the like) is potentially lower than the positive electrode and is on the negative potential side due to the configuration of the battery. The battery voltage appears as the sum of the potential differences in the electric double layer region of the positive electrode and the negative electrode. The electric double layer region is an angstrom-order thin layer region. The battery voltage of the lead-acid battery is equal to the difference between the potential on the positive electrode side and the potential on the negative electrode side with respect to the potential difference in the electric double layer region of the positive electrode and the negative electrode. The solid phase of the positive electrode active material has a positively charged electric double layer structure (that is, a high potential with respect to the electrolytic solution). On the other hand, the solid phase of the negative electrode active material has a negatively charged electric double layer structure (that is, a low potential with respect to the electrolytic solution).

Sulfate ion species generated from the lead sulfate or the like by charging reaction (SO _{4 ^2-,} HSO 4 ^-, etc.) is heavier than water in the electrolyte, and has a property of easily settle by gravity. Under PSOC, the battery is not fully charged, so it is difficult to stir the electrolytic solution by generating gas. As a result, the specific gravity of the electrolytic solution in the lower part of the battery becomes higher, and the specific gravity of the electrolytic solution in the upper part of the battery becomes lower, which means that the concentration of the electrolytic solution becomes non-uniform, which is called "stratification". When such a phenomenon occurs, the reaction area is reduced, so that the charge acceptance performance and the discharge performance are deteriorated.

As described above, the solid phase of the negative electrode active material, since they have charged electric double layer structure in the negative, sulfate ion species generated at the negative electrode side (SO _{4 ^2-,} HSO 4 ^-, etc.), a negative electrode Has an electrostatically repulsive relationship with. By this electrostatic repulsion is applied, the negative electrode side, a solid phase (e.g., the negative electrode active material of the pores) of the negative electrode active material by charging reaction generated ion species sulphate in (SO _{4 ^2-,} HSO 4 ^- etc.) are pushed in the electrolyte side and on the environment in which precipitation in the ionic species in the electrolyte sulfuric acid is accelerated.

On the other hand, in the lead storage battery according to the present embodiment, when at least a part of the second porous sheet is arranged between the first porous sheet and the negative electrode (for example, between the first porous sheet and the negative electrode). When the second porous sheet is arranged so as to come into contact with the surface of the negative electrode), the sulfate ion species extruded from the solid phase of the negative electrode active material toward the electrolytic solution settle in the electrolytic solution. Since it can be effectively suppressed, it is possible to further suppress the occurrence of stratification.

On the other hand, the solid phase of the positive electrode active material, since they have positively charged electric double layer structure, sulfate ion species generated in the positive electrode side (SO _{4 ^2-,} HSO 4 ^-, etc.), positive electrode and electrostatic It does not have a repulsive relationship. Therefore, even if the porous sheet is arranged on the positive electrode side (for example, even if the porous sheet is brought into contact with the surface of the positive electrode), the effect of avoiding stratification of the electrolytic solution is small. This is a configuration in which the porous sheet is not arranged on the negative electrode side (for example, the porous sheet is not brought into contact with the surface of the negative electrode), and the porous sheet is arranged on the positive electrode side outside the bag-shaped separator containing the negative electrode (for example,). Either a porous sheet is brought into contact with the surface of the positive electrode) or a porous sheet is arranged on the positive electrode side in a bag-shaped separator containing the positive electrode (for example, the porous sheet is brought into contact with the surface of the positive electrode). The same can be said for.

The second porous sheet may be in contact with the negative electrode, or may be in contact with the entire main surface of the negative electrode (for example, the electrode plate surface of the negative electrode plate). In the present embodiment, the negative electrode housed in the bag-shaped first porous sheet may be in contact with the second porous sheet in the first porous sheet.

When the second porous sheet is brought into contact with the surface of the negative electrode, it is preferable that the negative electrode and the second porous sheet are not integrated from the viewpoint of further suppressing stratification. For example, when the negative electrode and the porous sheet are integrated, the porous sheet that integrally contacts the surface of the negative electrode due to the entry of the negative electrode active material into the gap between the porous sheets is a cause of stratification. It may act as part of the solid phase of the negative electrode active material produced by the seed. In this case, the porous sheet, which is a part of the solid phase of the negative electrode active material, has the effect of suppressing the stratification phenomenon that becomes apparent due to the precipitation of sulfate ion species generated in the pores of the negative electrode active material and extruded to the electrolytic solution side. Tends to be small. Further, the porous sheet that integrally contacts the surface of the negative electrode may increase the internal resistance of the battery.

The separator preferably has a bag shape that encloses at least one of the positive electrode and the negative electrode. For example, it is preferable that one of the positive electrode and the negative electrode is housed in a bag-shaped separator and the other of the positive electrode and the negative electrode is alternately laminated. For example, when a bag-shaped separator is applied to the positive electrode, the negative electrode is housed in the bag-shaped separator (negative electrode storage bag) because the positive electrode current collector may penetrate the separator due to the elongation of the positive electrode current collector. Is preferable.

Each of the first perforated sheet and the second perforated sheet can be bent in half by the bent portion. Each of the first porous sheet and the second porous sheet may have a structure in which a part of the surface of the porous sheet faces the other part of the surface by bending the porous sheet. As such a configuration, for example, a configuration obtained by bending the porous sheet so that the cross section of the porous sheet exhibits a V-shape or a U-shape may be used. FIG. 1 is a cross-sectional view showing an example of a laminated structure of a positive electrode, a negative electrode, and a separator. However, in FIG. 1, the illustration of the misalignment prevention portion of the first embodiment is omitted. In FIG. 1, the positive electrode 10 and the negative electrode 20 are alternately laminated with the separator 30 interposed therebetween. The separator 30 includes a laminated sheet 60 having a first porous sheet 40 and a second porous sheet 50. The bag-shaped separator 30 accommodating the negative electrode 20 is, for example, obtained by stacking the first porous sheet 40 and the second porous sheet 50 to obtain a long laminated sheet 60, and then the center in the longitudinal direction of the laminated sheet 60. It can be obtained by arranging the negative electrode in the space formed by bending in the longitudinal direction, and further adhering the sheets on both sides adjacent to the bent portion to each other.

The configuration in which a part of the surface of the porous sheet faces the other part of the surface by bending the porous sheet is that the positions of the negative electrode and the porous sheet do not shift as compared with the case where the porous sheets are individually arranged on both sides of the negative electrode. Are better.

Further, in a liquid lead-acid battery, the electrodes tend to be arranged so that the main surface (electrode plate surface, etc.) of the electrodes (electrode plate, etc.) extends in the vertical direction. Therefore, when the length of the electrode is extended, it tends to be extended in the vertical direction. Under PSOC, lead sulfate tends to accumulate in the negative electrode, and lead sulfate tends to remain in the lower part of the negative electrode in the vertical direction. Since lead sulfate causes 2.7 times the volume expansion as compared with spongy lead, which is a negative electrode active material, when lead sulfate accumulates in the vertical lower part of the negative electrode, the lower part of the negative electrode tends to extend downward. In this case, the lower part of the deformed negative electrode may break through the porous sheet and cause a short circuit. On the other hand, in a configuration in which a part of the surface of the porous sheet faces the other part of the surface by bending the porous sheet, the lower part of the negative electrode tends to be located at the bent portion (bent portion) of the porous sheet having high strength. , It is possible to easily prevent the lower part of the deformed negative electrode from penetrating the porous sheet and causing a short circuit.

Examples of the constituent material of the first porous sheet include resin materials such as polyolefin (polyethylene, polypropylene, etc.) and polyethylene terephthalate. The first porous sheet is a microporous sheet or the like, and has, for example, a smaller porosity than the second porous sheet.

The constituent material of the second porous sheet is not particularly limited as long as it is a material having resistance to the electrolytic solution. Specific examples of the constituent material of the second porous sheet include organic fibers, inorganic fibers (glass fibers and the like), pulp, inorganic oxide powder and the like. The second porous sheet may contain at least one selected from the group consisting of organic fibers, glass fibers and pulp. As a constituent material of the second porous sheet, a mixed fiber containing an inorganic fiber and a pulp may be used, or an organic-inorganic mixed fiber containing an organic fiber and an inorganic fiber may be used. Examples of the organic fiber include polyolefin fiber (polyethylene fiber, polypropylene fiber, etc.), polyethylene terephthalate fiber, and the like. As the second porous sheet, for example, a porous sheet containing the constituent material as a main component can be used. As the constituent material of the second porous sheet, organic fibers are preferable from the viewpoint of suppressing an increase in the internal resistance of the battery.

When organic fibers are used as the constituent material of the second porous sheet, the workability is improved by improving the strength of the second porous sheet. On the other hand, when an inorganic fiber (glass fiber or the like) is used as a constituent material of the second porous sheet, the wettability of the electrolytic solution and the holding performance of the electrolytic solution of the second porous sheet are improved, and the charge acceptance performance is lowered. It can be easily suppressed. When pulp is used as a constituent material of the second porous sheet, the density of the second porous sheet is improved, and the short-circuit resistance can be further improved.

The second porous sheet may be a non-woven fabric. The non-woven fabric can appropriately contain an inorganic oxide powder such as silica. A non-woven fabric can be produced by dispersing fibers in water and making the paper, so if the inorganic oxide powder is dispersed in water together with the fibers at the time of papermaking, the non-woven fabric containing the inorganic oxide powder is produced. Can be easily obtained.

The non-woven fabric is preferably a mixed non-woven fabric containing glass fiber, pulp and silica powder as main components. As a non-woven fabric composed of such a mixture of a plurality of fibers, for example, a thin separator (separator applied to a control valve type lead-acid battery) disclosed in Japanese Patent Application Laid-Open No. 2002-260714 has a single structure of glass fiber. Instead, a separator having a structure containing glass fiber, acid-resistant organic resin fiber, and silica if necessary) can be preferably used.

It is preferable that at least one surface (main surface) of the second porous sheet is hydrophilized. By hydrophilizing the second porous sheet, the wettability of the electrolytic solution is improved, the electrical resistance when the electrolytic solution and the separator are in contact with each other is reduced, and the charge acceptance performance or the efficient discharge performance is further improved. Can be done. Both surfaces (main surfaces) of the second porous sheet may be hydrophilized, and only the surface (main surface) of the second porous sheet opposite to the first porous sheet is hydrophilized. May be.

As the hydrophilic treatment, plasma treatment, sulfonate treatment, surfactant treatment, fluorine gas treatment, corona discharge treatment and the like can be used, and from the viewpoint of high hydrophilicity, sulfonate treatment or fluorine gas treatment can be used. preferable. As the hydrophilic treatment, fluorine gas treatment is more preferable from the viewpoint of shortening the time of the hydrophilic treatment step.

By the sulfonate treatment, a sulfone group can be introduced on the surface of the second porous sheet to improve hydrophilicity. Examples of the fluorine gas treatment include a method of treating the second porous sheet with a mixed gas of fluorine gas and oxygen gas. By the fluorine gas treatment, at least one selected from the group consisting of a sulfone group, a carboxyl group and a hydroxyl group can be introduced into at least one surface of the second porous sheet to improve hydrophilicity. Since at least one surface of the second porous sheet has at least one selected from the group consisting of a sulfone group, a carboxyl group and a hydroxyl group, the hydrophilicity is improved and the electricity when the electrolytic solution and the separator come into contact with each other is improved. The resistance is lowered, and the charge acceptance performance or the discharge characteristic can be further improved.

As the average pore diameter of the second porous sheet, a pore diameter through which sulfate ions can permeate can be used. The average pore size of the second porous sheet is preferably in the following range from the viewpoint of easily suppressing the sedimentation of sulfate ions and further improving the charge acceptance performance and the cycle characteristics by having a good influence on the battery reaction. The average pore diameter of the second porous sheet is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, from the viewpoint of being able to sufficiently permeate sulfate ions and further improving the charge acceptance performance. 5 μm or more is particularly preferable, and 6 μm or more is extremely preferable. The average pore diameter of the second porous sheet is preferably 200 μm or less, more preferably 150 μm or less, further preferably 100 μm or less, from the viewpoint that sedimentation of sulfate ions can be sufficiently suppressed and the cycle characteristics are further improved. Preferably, 90 μm or less is particularly preferable, and 80 μm or less is extremely preferable. From these viewpoints, the average pore diameter of the second porous sheet is preferably 1 to 200 μm, more preferably 1 to 150 μm, further preferably 1 to 100 μm, particularly preferably 1 to 90 μm, and extremely preferably 1 to 80 μm. 2 to 80 μm is very preferable, 3 to 80 μm is even more preferable, 5 to 80 μm is more preferable, and 6 to 80 μm is even more preferable. The average pore diameter of the second porous sheet may be 10 μm or more, or 30 μm or more. The average pore diameter of the second porous sheet may be 10 to 100 μm or 30 to 90 μm.

FIG. 2A is a front view showing an example of the first porous sheet, and FIG. 2B is a cross-sectional view showing an example of the first porous sheet. FIG. 3 is a cross-sectional view showing an example of a laminated structure of a first porous sheet, a second porous sheet, and an electrode. As shown in FIG. 2, the first perforated sheet 40 includes a flat plate-shaped base portion 41, a plurality of convex (for example, linear) ribs (main ribs) 42, and mini ribs 43. The base portion 41 supports the rib 42 and the mini rib 43. The ribs 42 are arranged substantially parallel to each other on one surface 40a of the porous sheet 40. The distance between the ribs 42 is, for example, 3 to 15 mm. One end of the rib 42 in the height direction is integrally connected to the base portion 41, and the other end of the rib 42 in the height direction is in contact with the positive electrode 10 (see FIG. 3). The base portion 41 faces the positive electrode 10 in the height direction of the rib 42. No ribs are arranged on the other surface 40b of the porous sheet 40, and the other surface 40b of the porous sheet 40 is in contact with the second porous sheet 50 (see FIG. 3). One surface 50a of the porous sheet 50 is in contact with the porous sheet 40. The other surface 50b of the porous sheet 50 is in contact with the negative electrode 20.

A large number of mini ribs 43 are formed so as to extend in the longitudinal direction of the porous sheet 40 on both sides in the width direction of the porous sheet 40. The mini rib 43 has a function of improving the separator strength in order to prevent the corners of the electrodes from breaking through the separator and short-circuiting when the lead-acid battery vibrates in the lateral direction. The height, width and spacing of the mini ribs 43 are preferably smaller than those of the ribs 42. Further, the cross-sectional shape of the mini rib 43 may be the same as or different from that of the rib 42. The cross-sectional shape of the mini rib 43 is preferably a semicircular shape. Further, the mini rib 43 may not be formed.

The number of mini ribs is preferably 10 or more, and more preferably 20 or more, from the viewpoint that the edges of the porous sheet 40 are less likely to wrinkle when the separator is wound and the productivity is excellent, and the strength is improved. The number of mini ribs is preferably 40 or less from the viewpoint that the porous sheet 40 can be easily formed into a bag shape. From these viewpoints, the number of mini ribs is preferably 10 to 40, more preferably 20 to 40. When mini ribs are arranged at both ends of the perforated sheet 40 in the lateral direction, the number of the mini ribs is, for example, the number arranged at each of both ends.

As shown in FIG. 3, the separator 30 in the first embodiment has a misalignment prevention portion 70 that fixes the relative positions of the porous sheet 40 and the porous sheet 50 in the laminated sheet 60. The misalignment preventing means for forming the misalignment preventing portion 70 is not particularly limited as long as it is a means for preventing the relative positions of the perforated sheet 40 and the perforated sheet 50 from being displaced. Specifically, as the misalignment prevention means, heat welding, ultrasonic welding, adhesive, double-sided tape, crimping or the like can be used. Specifically, as the misalignment prevention portion 70, a heat welding portion, an ultrasonic welding portion, an adhesive, a double-sided tape, a crimping portion, or the like can be used. The misalignment prevention portion 70 may be formed inside the porous sheets 40 and 50, or may be formed outside the porous sheets 40 and 50 separately from the porous sheets 40 and 50. The misalignment prevention portion 70 in FIG. 3 is, for example, a heat welding portion. As the misalignment prevention unit 70, a heat welding unit or an ultrasonic welding unit is preferable from the viewpoint of further excellent productivity and economy.

When heat welding is used as the misalignment preventing means, the misalignment of the porous sheet 40 and the porous sheet 50 can be prevented without changing the total thickness of the porous sheet 40 and the porous sheet 50. Thereby, for example, the risk of failure when inserting the electrode into the electrode storage bag at the time of assembling the battery can be further reduced. In addition, the battery is easy to manufacture. However, when heat welding is performed, it is necessary to melt it, so it is preferable to use organic fibers as a constituent material of the porous sheet. The temperature range of heat welding is preferably 150 to 300 ° C. in consideration of the melting point of the constituent material of the porous sheet (polyethylene, polypropylene, polyethylene terephthalate, etc.).

When ultrasonic welding is used as a means for preventing misalignment, the friction between the ultrasonic vibrator and the porous sheets 40 and 50 is lower than that of heat welding. Therefore, organic fibers or pulp are used as the constituent material of the porous sheet 50. Even if there is, it is possible to easily prevent the displacement between the porous sheet 40 and the porous sheet 50 without changing the total thickness of the porous sheet 40 and the porous sheet 50.

When an adhesive or double-sided tape is used as a misalignment preventing means, not only organic fibers but also glass fibers that are difficult to weld can be used as the constituent material of the porous sheet. In particular, when an adhesive is used, the certainty of adhesion between the porous sheet 40 and the porous sheet 50 is high. The adhesive preferably has acid resistance. Examples of the components contained in the adhesive include atactic polypropylene, isotactic polypropylene, polyethylene, and polypropylene.

When crimping is used as a means for preventing misalignment, a large stress is applied to the porous sheet during crimping, so that the tensile strength of the porous sheet is preferably high. Therefore, when a material having high tensile strength (organic fiber, pulp, etc.) is used as a constituent material of the porous sheet, the displacement between the porous sheet 40 and the porous sheet 50 can be easily prevented.

The width of the misalignment prevention portion in the lateral direction of the perforated sheet 40 (welding width of heat welding, welding width of ultrasonic welding, adhesive width, pressure bonding width, etc.) has excellent strength (welding strength, adhesive strength, etc.). ) Is easy to obtain, preferably 0.3 mm or more, and more preferably 0.4 mm or more. From the viewpoint of further improving the battery performance, the width of the misalignment prevention portion of the porous sheet 40 in the lateral direction is preferably 2.0 mm or less, more preferably 1.6 mm or less, further preferably 1.5 mm or less. 4 mm or less is particularly preferable, 1.0 mm or less is extremely preferable, and 0.7 mm or less is very preferable. The width of the misalignment prevention portion can be calculated as, for example, an average value of the widths when observing any three points of the misalignment prevention portion with an optical microscope, a scanning electron microscope, or the like.

There is no particular limitation on the configuration of the misalignment prevention unit. The misalignment prevention unit can be arranged at any position. Examples of the shape of the misalignment prevention portion include a dot shape and a flat plate shape. The number of misalignment prevention portions may be one or a plurality. When a plurality of misalignment prevention portions are arranged, a plurality of misalignment prevention portions may be arranged along the longitudinal direction of the first perforated sheet.

The misalignment prevention portion is preferably arranged between the ribs from the viewpoint that the total thickness of the separator is unlikely to change.

The distance from the end of the first porous sheet (the end of the long side) to the end of the misalignment prevention portion in the lateral direction of the first porous sheet is such that the second porous sheet is difficult to bend and defects occur. From the viewpoint of difficulty, 35 mm or less is preferable, 33 mm or less is more preferable, 28 mm or less is further preferable, and 23 mm or less is particularly preferable. The distance from the end of the first porous sheet (the end of the long side) to the end of the misalignment prevention portion in the lateral direction of the first porous sheet is when the first porous sheet is formed in a bag shape. 4 mm or more is preferable, and 5 mm or more is more preferable, from the viewpoint that the first porous sheets can be easily joined to each other, the joined portion has sufficient strength, and defects derived from the misalignment prevention portion are less likely to occur. When a plurality of misalignment prevention portions are arranged, it is preferable that the shortest distance (shortest distance) among the distances of the plurality of misalignment prevention portions satisfies the range.

The distance from the end of the first porous sheet (the end of the long side) to the end of the misalignment prevention portion in the lateral direction of the first porous sheet is first from the viewpoint of easy manufacturing of the separator. It is preferable that the amount of exposure in the short side of the perforated sheet is larger than that of the above.

FIG. 4 is a drawing showing an example of a state in which the negative electrode 20 is housed in the bag-shaped separator 30. As shown in FIG. 2A described above, the porous sheet used for producing the separator 30 is formed, for example, in the form of a long sheet. The separator 30 is a porous sheet is cut to the appropriate length, crimping superimposed, the side portions are in the longitudinal direction clamshell perforated sheet arranged negative electrode 20 on its inner side (e.g., a mechanical seal) or heat welding (For example, reference numeral 32 in FIG. 4 is a mechanical seal portion). As a result, the separator 30 shown in FIG. 4 is obtained. The joint portion (mechanical seal portion or the like in FIG. 4) for forming the perforated sheet in a bag shape may be a misalignment prevention portion, and the joint portion and the misalignment prevention portion may be different. When the joint portion and the misalignment prevention portion are different, a bag-shaped separator is likely to be formed.

The upper limit of the thickness T1 of the base portion 41 is preferably 0.3 mm or less, more preferably 0.25 mm or less, still more preferably 0.2 mm or less, from the viewpoint of further improving charge acceptance performance and discharge characteristics. The lower limit of the thickness T1 of the base portion 41 is not particularly limited, but is preferably 0.05 mm or more, more preferably 0.1 mm or more, from the viewpoint of easily suppressing a short circuit.

The upper limit of the height (height of the base portion 41 and the positive electrode 10 in the opposite direction) H of the rib 42 is preferably 1.25 mm or less, more preferably 1.0 mm or less, from the viewpoint of obtaining more excellent charge acceptance performance. It is more preferably 0.75 mm or less. The lower limit of the height H of the rib 42 is preferably 0.3 mm or more, more preferably 0.4 mm or more, still more preferably 0.5 mm or more, from the viewpoint of further suppressing oxidative deterioration at the positive electrode.

The lower limit of the ratio H / T1 of the height H of the rib 42 to the thickness T1 of the base portion 41 is preferably 0.5 or more from the viewpoint of further excellent oxidation resistance of the separator. When the ratio H / T1 is 0.5 or more, it is presumed that the oxidation resistance of the separator is improved because a portion that does not come into contact with the electrode (for example, the positive electrode) can be sufficiently secured. The lower limit of the ratio H / T1 is more preferably 1 or more, and further preferably 2 or more, from the viewpoint of further excellent oxidation resistance and productivity of the separator.

The upper limit of the ratio H / T1 is preferably 6 or less from the viewpoint of excellent rib shape retention and further suppressing short circuit. When the ratio H / T1 is 6 or less, it is presumed that the short circuit is further suppressed because the distance between the positive electrode and the negative electrode is sufficient. Further, when the ratio H / T1 is 6 or less, it is presumed that the ribs are not damaged when the lead-acid battery is assembled, and the battery characteristics such as charge acceptance performance are maintained even better. The upper limit of the ratio H / T1 is more preferably 5 or less, further preferably 4.5 or less, and particularly preferably 4 or less, from the viewpoint of easily suppressing a short circuit and further excellent in shape retention of the rib.

The upper base width B of the rib 42 (see FIG. 2B) is preferably 0.1 to 2 mm, more preferably 0.2 to 1 mm, and 0, from the viewpoint of further excellent rib shape retention and oxidation resistance. .2 to 0.8 mm is more preferable. The lower bottom width A of the rib is preferably 0.2 to 4 mm, more preferably 0.3 to 2 mm, and even more preferably 0.4 to 1 mm from the viewpoint of excellent rib shape retention. The ratio (B / A) of the upper base width B to the lower base width A is preferably 0.1 to 1, more preferably 0.2 to 1, and 0.3 to 1 from the viewpoint of excellent rib shape retention. Is more preferable.

The upper limit of the thickness T2 of the porous sheet 50 is preferably 0.3 mm or less, more preferably 0.2 mm or less, still more preferably 0.1 mm or less, from the viewpoint of reducing charge transfer resistance. The lower limit of the thickness T2 of the porous sheet 50 is preferably 0.05 mm or more from the viewpoint of further suppressing stratification. From these viewpoints, the thickness T2 is preferably 0.05 to 0.3 mm, more preferably 0.05 to 0.2 mm, and even more preferably 0.05 to 0.1 mm.

The lower limit of the ratio T1 / T2 of the thickness T1 of the base portion 41 to the thickness T2 of the porous sheet 50 is preferably 0.3 or more from the viewpoint of reducing charge transfer resistance and further suppressing stratification. 4 or more is more preferable, and 0.5 or more is further preferable. The upper limit of the ratio T1 / T2 is preferably 5 or less, more preferably 4 or less, still more preferably 3 or less, from the viewpoint of reducing charge transfer resistance and further suppressing stratification.

The lower limit of the total thickness of the separator 30 (the sum of the thickness of the porous sheet 40 and the thickness of the porous sheet 50 (the sum of the thickness of the base portion 41 and the thickness of the rib 42)) is from the viewpoint of further suppressing permeation short circuit and stratification. , 0.6 mm or more is preferable, 0.7 mm or more is more preferable, and 0.8 mm or more is further preferable. The upper limit of the total thickness of the separator 30 is preferably 1.5 mm or less, more preferably 1.2 mm or less, still more preferably 1.0 mm or less, from the viewpoint of reducing charge transfer resistance.

The present embodiment is not limited to a mode in which the negative electrode is housed in a bag-shaped separator composed of a laminated sheet of a first porous sheet (porous sheet 40) and a second porous sheet (porous sheet 50), for example. The negative electrode and the single-wafer-shaped (not bag-shaped) second porous sheet may be housed in the bag-shaped separator made of the first porous sheet. Further, when the second porous sheet is arranged outside the bag-shaped separator, the positive electrode may be accommodated in the bag-shaped separator made of the first porous sheet. Further, at least a part of the second porous sheet may be arranged between the first porous sheet and the negative electrode, and the entire second porous sheet is arranged between the first porous sheet and the negative electrode. You may.

The method for producing a separator for a lead storage battery according to the present embodiment is to use the first porous sheet (porous sheet 40) so that the edge of the first porous sheet (porous sheet 40) is exposed from the second porous sheet (porous sheet 50). A laminating step of laminating the second porous sheet to obtain a separator is provided. The method for manufacturing a lead-acid battery separator according to the present embodiment may further include a step of forming a misalignment prevention portion (heat welding portion, ultrasonic welding portion, crimping portion, etc.) after the laminating step. Good. The method for manufacturing a separator for a lead storage battery according to the present embodiment includes a laminating step of laminating the first porous sheet and the second porous sheet via a misalignment prevention portion (adhesive, double-sided tape, etc.). It may be an embodiment.

(Positive material)
[Positive electrode active material]
The positive electrode material contains a positive electrode active material. The positive electrode active material can be obtained by aging and drying a positive electrode material paste containing a raw material for the positive electrode active material to obtain an unchemicald active material and then chemicalizing the paste. The positive electrode active material after chemical conversion preferably contains α-lead dioxide (α-PbO ₂ ), and may further contain β-lead dioxide (β-PbO ₂ ). The raw material for the positive electrode active material is not particularly limited, and examples thereof include lead powder. As the lead powder, for example, lead powder produced by a ball mill type lead powder manufacturing machine or a barton pot type lead powder manufacturing machine (in a ball mill type lead powder manufacturing machine, a mixture of powder of the main component PbO and scaly metal lead). ). Lead tan (Pb ₃ O ₄ ) may be used as a raw material for the positive electrode active material. The unchemical positive electrode material preferably contains an unchemical positive electrode active material containing tribasic lead sulfate as a main component.

The average particle size of the positive electrode active material is preferably 0.3 μm or more, more preferably 0.5 μm or more, still more preferably 0.7 μm or more, from the viewpoint of further improving charge acceptance performance and cycle characteristics. The average particle size of the positive electrode active material is preferably 2.5 μm or less, more preferably 2 μm or less, still more preferably 1.5 μm or less, from the viewpoint of further improving the cycle characteristics. The average particle size of the positive electrode active material is the average particle size of the positive electrode active material in the positive electrode material after chemical conversion. The average particle size of the positive electrode active material is, for example, the long side length of all the particles in the image of the scanning electron micrograph (1000 times) in the range of 10 μm in length × 10 μm in width in the central portion of the positive electrode material after chemical conversion. The value of (maximum particle size) can be obtained as an arithmetically averaged value.

[Positive electrode additive]
The positive electrode material may further contain an additive. Examples of the additive include carbon materials, reinforcing short fibers (excluding carbon fibers) and the like. Examples of the carbon material include a carbonaceous conductive material. Examples of the carbonaceous conductive material include graphite, carbon black, activated carbon, carbon fibers, carbon nanotubes and the like. Examples of carbon black include furnace black (Ketjen black, etc.), channel black, acetylene black, thermal black, and the like. As the carbonaceous conductive material, the same material as the negative electrode additive can be used. Examples of the reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers and the like.

[Physical properties of positive electrode material]
The lower limit of the specific surface area of the positive electrode material is preferably 3 m ² / g or more, more preferably 4 m ² / g or more, still more preferably 5 m ² / g or more, from the viewpoint of further excellent charge acceptance performance. The upper limit of the specific surface area of the cathode material is not particularly limited, from the viewpoint of excellent practical point of view and utilization, preferably ^{15 m} 2 / g or less, more preferably ^13m 2 / g or less, it is ^12m 2 / g or less More preferred. The specific surface area of the positive electrode material is the specific surface area of the positive electrode material after chemical conversion. The specific surface area of the positive electrode material is, for example, a method of adjusting the amount of sulfuric acid and water added when preparing the positive electrode material paste, a method of refining the active material at the stage of the unchemically active material, a method of changing the chemical conversion conditions, and the like. Can be adjusted by.

The specific surface area of the positive electrode material can be measured by, for example, the BET method. The BET method is a method in which an inert gas (for example, nitrogen gas) having a known molecular size is adsorbed on the surface of a measurement sample, and the surface area is obtained from the adsorbed amount and the occupied area of the inert gas. This is a general method for measuring surface area. Specifically, the measurement is performed based on the following BET formula.

Relationship of the following formula (1), _P / P _o is established well in the range of 0.05 to 0.35. The details of each code in the equation (1) are as follows.
P: adsorption equilibrium pressure P o when an adsorption equilibrium state at a constant _temperature: the saturated vapor pressure at the adsorption temperature V: adsorption equilibrium pressure adsorption amount of P V _m: monomolecular monolayer adsorption amount (gas molecules solid surface Adsorption amount when forming a layer)
C: BET constant (parameter regarding the interaction between the solid surface and the adsorbed substance)

The following formula (2) can be obtained by modifying the formula (1) (dividing the numerator denominator on the left side by P). In the specific surface area meter used for the measurement, gas molecules having a known adsorption area are adsorbed on the sample, and the relationship between the adsorption amount (V) and the relative pressure (P / _Po ) is measured. Than the measured V and _P / P _o, to plot the left side and the _P / P _o of the formula (2). Here, assuming that the gradient is s, the following equation (3) is derived from the equation (2). Assuming that the intercept is i, the intercept i and the gradient s are as shown in the following equations (4) and (5), respectively.

By modifying the formulas (4) and (5), the following formulas (6) and (7) are obtained, respectively, and the following formula (8) for obtaining the adsorption amount V _m of the monolayer is obtained. That is, when the adsorption amount V at a certain relative pressure P / _Po is measured at several points and the gradient and intercept of the plot are obtained, the adsorption amount V _{m of the} monolayer is obtained.

The total surface area S _total (m ² ) of the sample is calculated by the following formula (9), and the specific surface area S (m ² / g) is calculated by the following formula (10) from the total surface area S _total . In the formula (9), N denotes the Avogadro's _{number, A CS} shows the adsorption cross sectional area ^{(m 2),} M indicates the molecular weight. Further, in the formula (10), w represents the sample amount (g).

The porosity of the positive electrode material is preferably 50% by volume or more, more preferably 55% by volume or more, from the viewpoint that the region in which sulfuric acid enters the pores in the positive electrode material increases and the capacity tends to increase. The upper limit of the porosity of the positive electrode material is not particularly limited, but 70% by volume or less is preferable from the viewpoint that the amount of sulfuric acid impregnated into the pores in the positive electrode material is appropriate and the bonding force between the active materials can be maintained well. .. The upper limit of the porosity is more preferably 60% by volume or less from a practical point of view. The porosity of the positive electrode material is the porosity of the positive electrode material after chemical conversion. The porosity of the positive electrode material is, for example, a value (volume-based ratio) obtained from mercury porosimeter measurement. The porosity of the positive electrode material can be adjusted, for example, by the amount of dilute sulfuric acid added when the positive electrode material paste is prepared.

(Negative electrode material)
[Negative electrode active material]
The negative electrode active material can be obtained by aging and drying a negative electrode material paste containing a raw material for the negative electrode active material to obtain an unchemicald active material and then chemicalizing the paste. Examples of the negative electrode active material after chemical conversion include spongy lead and the like. The spongy lead reacts with sulfuric acid in the electrolytic solution and tends to gradually change to lead sulfate (PbSO ₄ ). Examples of the raw material for the negative electrode active material include lead powder and the like. As the lead powder, for example, lead powder produced by a ball mill type lead powder manufacturing machine or a barton pot type lead powder manufacturing machine (in a ball mill type lead powder manufacturing machine, a mixture of powder of the main component PbO and scaly metal lead). ). The unchemical negative electrode active material is composed of, for example, basic lead sulfate, metallic lead, and a lower oxide.

The average particle size of the negative electrode active material is preferably 0.3 μm or more, more preferably 0.5 μm or more, still more preferably 0.7 μm or more, from the viewpoint of further improving charge acceptance performance and cycle characteristics. The average particle size of the negative electrode active material is preferably 2.5 μm or less, more preferably 2 μm or less, still more preferably 1.5 μm or less, from the viewpoint of further improving the cycle characteristics. The average particle size of the negative electrode active material is the average particle size of the negative electrode active material in the negative electrode material after chemical conversion. The average particle size of the negative electrode active material is, for example, the long side length of all the particles in the scanning electron micrograph (1000 times) in the range of 10 μm in length × 10 μm in width in the central portion of the negative electrode material after chemical conversion. The value of (maximum particle size) can be obtained as an arithmetically averaged value.

[Negative electrode additive]
The negative electrode material may further contain an additive. Examples of the additive include organic compounds; barium sulfate; carbon materials; short reinforcing fibers (excluding carbon fibers) and the like. As the reinforcing short fiber, the same material as the positive electrode additive can be used. As the organic compound, for example, a resin (sulfone) having at least one selected from the group consisting of a sulfonic acid group (sulfonic acid group, sulfo group) and a sulfonic acid base (group in which the hydrogen atom of the sulfonic acid group is replaced with an alkali metal, etc.). Resins having groups and / or sulfonic acid bases). By including the resin having at least one selected from the group consisting of a sulfone group and a sulfonic acid base in the negative electrode material, it is possible to easily suppress the coarsening of the negative electrode active material due to charging and discharging, and the charge acceptance performance can be improved. It can be further improved.

Examples of the resin having a sulfonic acid group and / or a sulfonic acid base include bisphenol-based resins, lignin sulfonic acid, and lignin sulfonate. Ligno sulfonic acid is a compound in which a part of the decomposition product of lignin is sulfonated. Examples of the lignin sulfonate include potassium lignin sulfonate and sodium lignin sulfonate. Among these, bisphenol-based resins are preferable from the viewpoint of further improving charge acceptance performance.

The bisphenol resin is at least one selected from the group consisting of bisphenol compounds, amino acids, amino acid derivatives, aminoalkyl sulfonic acids, aminoalkyl sulfonic acid derivatives, aminoaryl sulfonic acids and aminoaryl sulfonic acid derivatives, and formaldehyde and formaldehyde derivatives. It is preferable that the resin is obtained by reacting with at least one selected from the group consisting of. Since the bisphenol resin has a sulfonic acid group and / or a sulfonic acid base, at least one of the compounds used in the reaction has a sulfonic acid group and / or a sulfonic acid base.

The bisphenol compound is a compound having two hydroxyphenyl groups. Examples of the bisphenol compound include 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as "bisphenol A"), bis (4-hydroxyphenyl) methane, and 1,1-bis (4-hydroxyphenyl) ethane. 2,2-Bis (4-hydroxyphenyl) hexafluoropropane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) butane, bis (4-hydroxy) Phenyl) diphenylmethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, bis (4-hydroxyphenyl) sulfone (hereinafter, " Bisphenol S ") and the like.

Examples of amino acids include glycine, alanine, phenylalanine, aspartic acid, glutamic acid and the like. Examples of the amino acid derivative include an alkali metal salt in which the hydrogen atom of the carboxyl group of the amino acid is replaced with an alkali metal (for example, sodium or potassium). Examples of the aminoalkyl sulfonic acid include aminomethanesulfonic acid, 2-aminoethanesulfonic acid, 3-aminopropanesulfonic acid, 2-methylaminoethanesulfonic acid and the like. The aminoalkyl sulfonic acid derivative, a compound wherein the hydrogen atom of the aminoalkyl sulfonic acid being substituted by an alkyl group (e.g., an alkyl group having 1 to 5 carbon atoms), and, a sulfone group (-SO ₃ H aminoalkyl sulphonic acids ) Is an alkali metal salt in which the hydrogen atom is replaced with an alkali metal (for example, sodium or potassium). Examples of the aminoarylsulfonic acid include aminobenzenesulfonic acid (4-aminobenzenesulfonic acid and the like), aminonaphthalenesulfonic acid and the like. The aminoaryl sulfonic acid derivative, a compound wherein the hydrogen atom of the amino aryl sulfonic acid being substituted by an alkyl group (e.g., an alkyl group having 1 to 5 carbon atoms) or the like, a sulfonic group of aminoaryl sulfonic acid (-SO 3 _H) Examples thereof include an alkali metal salt in which a hydrogen atom is replaced with an alkali metal (for example, sodium or potassium).

Examples of the formaldehyde derivative include paraformaldehyde, hexamethylenetetramine, trioxane and the like.

The bisphenol resin preferably has at least one selected from the group consisting of the structural unit represented by the following formula (I) and the structural unit represented by the following formula (II).

［式（Ｉ）中、Ｘ^１は、２価の基を示し、Ａ^１は、炭素数１〜４のアルキレン基、又は、アリーレン基を示し、Ｒ^１１は、アルカリ金属又は水素原子を示し、Ｒ^１２は、メチロール基（−ＣＨ_２ＯＨ）を示し、Ｒ^１３及びＲ^１４は、それぞれ独立にアルカリ金属又は水素原子を示し、ｎ１１は、１〜６００の整数を示し、ｎ１２は、１〜３の整数を示し、ｎ１３は、０又は１を示す。］

[In the formula (I), X ¹ represents a divalent group, A ¹ represents an alkylene group having 1 to 4 carbon atoms or an arylene group, and R ¹¹ represents an alkali metal or a hydrogen atom. R ¹² represents a methylol group (-CH ₂ OH), R ¹³ and R ¹⁴ each independently represent an alkali metal or a hydrogen atom, n 11 represents an integer of 1 to 600, and n 12 represents 1-3. Indicates an integer of, and n13 indicates 0 or 1. ]

［式（ＩＩ）中、Ｘ^２は、２価の基を示し、Ａ^２は、炭素数１〜４のアルキレン基、又は、アリーレン基を示し、Ｒ^２１は、アルカリ金属又は水素原子を示し、Ｒ^２２は、メチロール基（−ＣＨ_２ＯＨ）を示し、Ｒ^２３及びＲ^２４は、それぞれ独立にアルカリ金属又は水素原子を示し、ｎ２１は、１〜６００の整数を示し、ｎ２２は、１〜３の整数を示し、ｎ２３は、０又は１を示す。］

[In formula (II), X ² represents a divalent group, A ² represents an alkylene group having 1 to 4 carbon atoms or an arylene group, and R ²¹ represents an alkali metal or a hydrogen atom. R ²² represents a methylol group (-CH ₂ OH), R ²³ and R ²⁴ each independently represent an alkali metal or a hydrogen atom, n21 represents an integer of 1 to 600, and n ²² represents 1-3. Indicates an integer of, and n23 indicates 0 or 1. ]

The ratio of the structural unit represented by the formula (I) and the structural unit represented by the formula (II) is not particularly limited and may change depending on the synthesis conditions and the like. As the bisphenol resin, a resin having only one of the structural unit represented by the formula (I) and the structural unit represented by the formula (II) may be used.

Examples of X ¹ and X ² include an alkylidene group (methylidene group, ethylidene group, isopropylidene group, sec-butylidene group, etc.), a cycloalkylidene group (cyclohexylidene group, etc.), and a phenylalkylidene group (diphenylmethylidene group, etc.). Organic groups such as phenylethylidene group); sulfonyl groups are mentioned, and isopropylidene groups (-C (CH ₃ ) _2- ) groups are preferable from the viewpoint of further excellent charge acceptance performance, and from the viewpoint of further excellent discharge characteristics. A sulfonyl group (-SO _2- ) is preferred. X ¹ and X ² may be substituted with a halogen atom such as a fluorine atom. When X ¹ and X ² are cycloalkylidene groups, the hydrocarbon ring may be substituted with an alkyl group or the like.

Examples of A ¹ and A ² include an alkylene group having 1 to 4 carbon atoms such as a methylene group, an ethylene group, a propylene group and a butylene group; and a divalent arylene group such as a phenylene group and a naphthylene group. The arylene group may be substituted with an alkyl group or the like.

Examples of the alkali metals of R ¹¹ , R ¹³ , R ¹⁴ , R ²¹ , R ²³ and R ²⁴ include sodium and potassium. n11 and n21 are preferably 5 to 300 from the viewpoint of further excellent cycle characteristics and solubility in a solvent. n12 and n22 are preferably 1 or 2, and more preferably 1 from the viewpoint of improving charge acceptance performance, discharge characteristics, and cycle characteristics in a well-balanced manner. Although n13 and n23 vary depending on the production conditions, 0 is preferable from the viewpoint of further excellent cycle characteristics and excellent storage stability of the bisphenol resin.

The weight average molecular weight of a resin having a sulfone group and / or a sulfonic acid base (bisphenol resin, etc.) is to prevent the resin having a sulfone group and / or a sulfonic acid base from eluting from an electrode to an electrolytic solution in a lead storage battery. From the viewpoint that the cycle characteristics are easily improved, 3000 or more is preferable, 10,000 or more is more preferable, 20000 or more is further preferable, and 30,000 or more is particularly preferable. The weight average molecular weight of the resin having a sulfone group and / or a sulfonic acid base is 200,000 or less from the viewpoint that the cycle characteristics can be easily improved by suppressing the decrease in adsorptivity to the electrode active material and the decrease in dispersibility. Is preferable, 150,000 or less is more preferable, and 100,000 or less is further preferable.

The weight average molecular weight of the resin having a sulfone group and / or a sulfonic acid base can be measured, for example, by gel permeation chromatography (hereinafter referred to as “GPC”) under the following conditions.

{GPC condition}
Equipment: High Performance Liquid Chromatograph LC-2200 Plus (manufactured by JASCO Corporation)
Pump: PU-2080
Differential refractometer: RI-2031
Detector: Ultraviolet-visible absorptiometer UV-2075 (λ: 254 nm)
Column oven: CO-2065
Columns: TSKgel SuperAW (4000), TSKgel SuperAW (3000), TSKgel SuperAW (2500) (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Eluent: Methanol solution containing LiBr (10 mmol / L) and triethylamine (200 mmol / L) Flow velocity: 0.6 mL / min Molecular weight standard sample: Polyethylene glycol (molecular weight: 1.10 x 10 ⁶ , 5.80 x 10 ⁵⁾ , 2.55 × 10 ⁵ , 1.46 × 10 ⁵ , 1.01 × 10 ⁵ , 4.49 × 10 ⁴ , 2.70 × 10 ⁴ , 2.10 × 10 ⁴ ; manufactured by Tosoh Corporation), Diethylene glycol (molecular weight: 1.06 × 10 ^2; manufactured by Kishida chemical Co., Ltd.), dibutylhydroxytoluene (molecular weight: 2.20 × 10 ^2; manufactured by Kishida chemical Co., Ltd.)

Examples of the carbon material include a carbonaceous conductive material. As the carbonaceous conductive material, the same material as the positive electrode additive can be used. As the carbonaceous conductive material, at least one selected from the group consisting of graphite, carbon black, activated carbon, carbon fibers and carbon nanotubes is preferable, graphite is more preferable, and scaly graphite is further preferable. The blending amount of the carbonaceous conductive material is preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the negative electrode active material (sponge-like metallic lead or the like) in a fully charged state.

Here, "scaly graphite" refers to the one described in JIS M 8601 (2005). The electrical resistivity of scaly graphite is 0.02 Ω · cm or less, which is an order of magnitude smaller than the electrical resistivity of carbon black such as acetylene black, which is around 0.1 Ω · cm. Therefore, by using scaly graphite instead of carbon black used in the conventional lead-acid battery, the electric resistance of the negative electrode active material can be lowered and the charge acceptance performance can be further improved.

The average primary particle size of the scaly graphite is preferably 100 μm or more. The average primary particle size of scaly graphite can be determined according to the laser diffraction / scattering method described in JIS M 8511 (2005). For example, a commercially available surfactant polyoxyethylene octylphenyl ether (for example, Roche Diagnostics Co., Ltd.) is used as a dispersant using a laser diffraction / scattering particle size distribution measuring device (Nikkiso Co., Ltd .: Microtrack 9220FRA). Manufacture: An appropriate amount of scaly graphite is added to an aqueous solution containing 0.5% by volume of Triton X-100), and 40 W ultrasonic waves are irradiated for 180 seconds with stirring, and then measurement is performed. The value of the obtained average particle size (median diameter: D50) can be used as the average primary particle size.

Lead-acid batteries mounted on ISS vehicles, power generation control vehicles, micro-hybrid vehicles, etc. are used in a partially charged state called PSOC. In lead-acid batteries used under such circumstances, a phenomenon called "sulfation" occurs in which lead sulfate, which is an insulator generated in the negative electrode active material during discharge, becomes coarser with repeated charging and discharging. Occurs early. When sulfation occurs, the charge acceptance performance and discharge performance of the negative electrode active material may be significantly deteriorated. On the other hand, by using the negative electrode active material and the carbonaceous conductive material in combination, the coarsening of lead sulfate is easily suppressed and the lead sulfate is easily maintained in a fine state. As a result, lead ions are easily dissolved from lead sulfate, so that a state of high charge acceptance performance can be easily maintained.

[Physical properties of negative electrode material]
The specific surface area of the negative electrode material is preferably 0.4 m ² / g or more, more preferably 0.5 m ² / g or more, and 0.6 m ² / g or more, from the viewpoint of enhancing the reactivity between the electrolytic solution and the negative electrode active material. Is more preferable. The specific surface area of the negative electrode material, from the further suppression of the contraction of the negative electrode at the time of the cycle is preferably not more than ^2m 2 / g, more preferably not more than 1.8 m ² / g, more preferably not more than 1.5 m ² / g. The specific surface area of the negative electrode material is the specific surface area of the negative electrode material after chemical conversion. The specific surface area of the negative electrode material is, for example, a method of adjusting the amount of sulfuric acid and water added when preparing the negative electrode material paste, a method of refining the active material at the stage of the unchemically active material, a method of changing the chemical conversion conditions, and the like. Can be adjusted by. The specific surface area of the negative electrode material can be measured by, for example, the BET method.

(Current collector)
Examples of the current collector include a cast lattice, an expanded lattice, and the like. Examples of the material of the current collector include lead-calcium-tin alloy, lead-calcium alloy and lead-antimony alloy. A small amount of selenium, silver, bismuth and the like can be added to these. For example, a current collector can be obtained by forming these materials in a grid pattern by a gravity casting method, an expanding method, a punching method, or the like. The current collectors of the positive electrode and the negative electrode may be the same as each other or may be different from each other.

<Manufacturing method of lead-acid battery>
The method for manufacturing a lead-acid battery according to the present embodiment includes, for example, an electrode manufacturing step for obtaining electrodes (positive electrode and negative electrode) and an assembly step for assembling constituent members including the electrodes to obtain a lead-acid battery. The assembly step is, for example, a step of obtaining a lead storage battery using a positive electrode, a negative electrode, and a separator.

In the electrode manufacturing process, for example, an electrode material paste (positive electrode material paste and negative electrode material paste) is filled in a current collector (for example, a current collector lattice such as a cast lattice or an expanded lattice), and then aged and dried. Thereby, an unchemical electrode is obtained. The positive electrode material paste contains, for example, a raw material (lead powder or the like) for the positive electrode active material, and may further contain other additives. The negative electrode material paste contains a raw material (lead powder, etc.) for the negative electrode active material, and preferably contains a resin having a sulfone group and / or a sulfonic acid base (bisphenol resin, etc.) as a dispersant. , Other additives may be further contained.

The positive electrode material paste for obtaining the positive electrode material can be obtained, for example, by the following method. In producing the positive electrode material paste, lead tan (Pb ₃ O ₄ ) may be used as a raw material for the positive electrode active material from the viewpoint of shortening the chemical conversion time.

First, an additive (reinforcing short fibers or the like) is added to the raw material of the positive electrode active material and dry-mixed to obtain a mixture. Then, sulfuric acid (dilute sulfuric acid or the like) and a solvent (water such as ion-exchanged water, an organic solvent, etc.) are added to this mixture and kneaded to obtain a positive electrode material paste.

An unchemicald positive electrode can be obtained by filling a current collector (for example, a current collector lattice such as a cast lattice or an expanded lattice) with a positive electrode material paste and then aging and drying.

When reinforcing short fibers are used in the positive electrode material paste, the blending amount of the reinforcing short fibers is preferably 0.005 to 0.3% by mass based on the total mass of the raw material (lead powder, etc.) of the positive electrode active material. More preferably, 0.05 to 0.3% by mass.

The aging conditions for obtaining an unmodified positive electrode are preferably 15 to 60 hours in an atmosphere having a temperature of 35 to 85 ° C. and a humidity of 50 to 98 RH%. The drying conditions are preferably 15 to 30 hours at a temperature of 45 to 80 ° C.

The negative electrode material paste can be obtained, for example, by the following method. First, an additive (resin having a sulfone group and / or a sulfonic acid base, reinforcing short fibers, barium sulfate, etc.) is added to the raw material of the negative electrode active material and dry-mixed to obtain a mixture. Then, sulfuric acid (dilute sulfuric acid or the like) and a solvent (water such as ion-exchanged water, an organic solvent, etc.) are added to this mixture and kneaded to obtain a negative electrode material paste. An unmodified negative electrode can be obtained by filling a current collector (for example, a current collector lattice such as a cast lattice or an expanded lattice) with this negative electrode material paste, and then aging and drying.

When an organic compound (resin having a sulfone group and / or a sulfonic acid base such as a bisphenol resin), a carbon material, reinforcing short fibers or barium sulfate is used in the negative electrode material paste, the blending amount of each component is in the following range. Is preferable. The blending amount of the organic compound (in the case of a resin having a sulfonic acid group and / or a sulfonic acid base, the blending amount in terms of resin solid content) is 0, based on the total mass of the raw material (lead powder, etc.) of the negative electrode active material. It is preferably 01 to 2.0% by mass, more preferably 0.05 to 1.0% by mass, further preferably 0.1 to 0.5% by mass, and particularly preferably 0.1 to 0.3% by mass. The blending amount of the carbon material is preferably 0.1 to 3% by mass, more preferably 0.2 to 2.5% by mass, based on the total mass of the raw material (lead powder or the like) of the negative electrode active material. The blending amount of the reinforcing short fibers is preferably 0.05 to 0.15% by mass based on the total mass of the raw material (lead powder or the like) of the negative electrode active material. The blending amount of barium sulfate is preferably 0.01 to 2.0% by mass, more preferably 0.01 to 1.0% by mass, based on the total mass of the raw material (lead powder or the like) of the negative electrode active material.

The aging conditions for obtaining an unmodified negative electrode are preferably 15 to 30 hours in an atmosphere of a temperature of 45 to 65 ° C. and a humidity of 70 to 98 RH%. The drying conditions are preferably 15 to 30 hours at a temperature of 45 to 60 ° C.

In the assembly process, for example, the unchemical negative electrode and the unchemical positive electrode produced as described above are alternately laminated via a separator, and the current collectors of electrodes having the same polarity are connected (welded, etc.) with a strap. Obtain a group of electrodes. This group of electrodes is arranged in the battery case to produce an unmodified battery. Next, after injecting the electrolytic solution into the non-chemical battery, a direct current is applied to form an electric tank. A lead storage battery can be obtained by adjusting the specific gravity of the electrolytic solution after chemical conversion to an appropriate specific gravity.

The electrolytic solution contains, for example, sulfuric acid. The electrolytic solution preferably contains alkali metal ions from the viewpoint of further excellent life performance. As the alkali metal ion, at least one selected from the group consisting of lithium ion, sodium ion and potassium ion is preferable. Among these, sodium ions are more preferable from the viewpoint of further suppressing osmotic short circuits. The electrolytic solution containing alkali metal ions can be obtained by mixing sulfuric acid with powder of sulfate such as lithium sulfate, sodium sulfate, potassium sulfate and the like. Anhydride or hydrate can be used as the sulfate salt to be dissolved in the electrolytic solution.

The specific gravity of the electrolytic solution after chemical conversion is preferably in the following range. The specific gravity of the electrolytic solution is preferably 1.25 or more, more preferably 1.26 or more, further preferably 1.27 or more, and 1.275 or more, from the viewpoint of suppressing permeation short circuit or freezing and further excellent discharge characteristics. Especially preferable. The specific gravity of the electrolytic solution is preferably 1.33 or less, more preferably 1.32 or less, further preferably 1.315 or less, and particularly preferably 1.31 or less, from the viewpoint of further improving charge acceptance performance and cycle characteristics. The value of the specific gravity of the electrolytic solution can be measured by, for example, a floating hydrometer or a digital hydrometer manufactured by Kyoto Denshi Kogyo Co., Ltd.

When the electrolytic solution contains alkali metal ions, the alkali metal ion concentration is preferably 0.06 mol / L or more, preferably 0.1 mol / L, based on the total amount of the electrolytic solution, from the viewpoint of further improving charge acceptance performance and cycle characteristics. L or more is more preferable. The alkali metal ion concentration of the electrolytic solution is preferably 0.14 mol / L or less based on the total amount of the electrolytic solution from the viewpoint of further improving the charge acceptance performance and the cycle characteristics. The alkali metal ion concentration of the electrolytic solution can be measured by, for example, ICP emission spectroscopic analysis (high frequency inductively coupled plasma emission spectroscopic analysis).

The details of the mechanism by which the cycle characteristics are improved when the alkali metal ion concentration of the electrolytic solution is within the predetermined range are not clear, but are presumed as follows. That is, when the alkali metal ion concentration is within the predetermined range, the alkali metal is likely to precipitate in the separator (particularly, the surface layer portion), so that the precipitation of lead in the separator is easily suppressed and the precipitate grows. Since it is difficult to do so, it is considered that the cycle characteristics are improved by easily suppressing short circuits (penetration short circuits, etc.).

The battery case is a member capable of accommodating electrodes (electrode plates, etc.) inside. From the viewpoint of easy storage of electrodes, the battery case is preferably a member having a box body having an open upper surface and a lid body covering the upper surface of the box body. An adhesive, heat welding, laser welding, ultrasonic welding, or the like can be appropriately used for bonding the box body and the lid body. The shape of the battery case is not particularly limited, but a square shape is preferable so that the invalid space is reduced when the electrodes are stored.

The material of the battery case is not particularly limited, but needs to be a material having resistance to an electrolytic solution (dilute sulfuric acid or the like). Specific examples of the material of the battery case include PP (polypropylene), PE (polyethylene), ABS resin and the like. When the material is PP, it is advantageous in terms of acid resistance, processability (heat welding of the battery case and the lid is difficult with ABS resin), and cost.

When the battery case is composed of a box body and a lid body, the materials of the box body and the lid body may be the same material or different materials from each other. From the viewpoint of not generating unreasonable stress, materials having the same coefficient of thermal expansion are preferable.

The chemical conversion conditions and the specific gravity of sulfuric acid can be adjusted according to the properties of the electrode active material. Further, the chemical conversion treatment is not limited to being carried out after the assembly step, and may be carried out after aging and drying in the electrode manufacturing step (tank chemical conversion).

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples.

<Test A: Evaluation of bending during fabrication of lead-acid battery storage bag>
(Making separators for lead-acid batteries)
[Example 1A]
Eight ribs (rib spacing: 9.8 mm, rib width (upper base width and lower base width): 0.8 mm, rib height: 0.55 mm) and mini ribs (rib spacing: 1.0 mm, rib width (upper) Bottom width and bottom bottom width): 0.3 mm, rib height: 0.2 mm) on one side, a long sheet made of microporous polyethylene (hereinafter referred to as "Sheet A") "Sheet A" manufactured by Nippon Plate Glass Co., Ltd. Microporous sheet ". Base width: 115 mm, base thickness: 0.20 mm) and a porous sheet made of polyethylene whose surface (both sides) are hydrophilized with sulfone groups (hereinafter referred to as" sheet B1 ". Japan Bileen Co., Ltd.""Non-wovenfabric" manufactured by the company. Width: 100 mm, thickness: 0.1 mm, average pore diameter: 1 μm, grain size: 40 g / m ² ) was prepared. Each of the rib and the mini rib is arranged substantially parallel to each other in the lateral direction of the seat A. Twenty mini-ribs are arranged at both ends of the seat A in the lateral direction. Next, the sheet A and the sheet B1 were overlapped with each other so that the surface of the sheet A having no ribs and the sheet B1 were in contact with each other to obtain a laminated sheet. Then, the laminated sheet was sandwiched between heaters having a set temperature of 250 ° C.

The width of the base portion of the sheet A is 115 mm, the width of the sheet B1 is 100 mm, and the sheet B1 is arranged on the sheet A so that the sheet B1 is positioned approximately in the center of the sheet A. That is, the sheet A and the sheet B1 were arranged so that both ends of the sheet A protruded 7.5 mm from both ends of the sheet B1.

The average pore diameter was calculated as the value of Median Pole Diameter (Volume) in the measurement result obtained from the mercury porosimeter measurement. The measurement conditions for mercury porosimeter measurement are as follows.
・ Equipment: Shimadzu Corporation, Autopore IV 9500
-Mercury press-fitting pressure: 0.51 psia
・ Pressure holding time at measured pressure: 10 seconds ・ Contact angle between sample and mercury: 140 °
-Surface tension of mercury: 485 days / cm
-Mercury density: 13.535g / mL

The position sandwiched by the heater is 20 mm from both ends on the long side of the sheet B1 (distance from the end of the sheet B1 to the end of the misalignment prevention portion (shortest distance). The long side of the sheet A). A total of two locations (positions 27.5 mm from both ends of the sheet A) were selected so that the ribs of the sheet A did not interfere with each other. The ribs were arranged so that the longitudinal direction of the ribs coincided with the longitudinal direction of the sheet B1. After sandwiching with a heater, while winding the laminated sheet at a speed of 20 m / min, the sheet A and the sheet B1 are continuously partially heat-welded (position misalignment prevention means. Width of the misalignment prevention portion (sheet A). Width in the lateral direction. The same applies hereinafter): 1.0 mm each, welding temperature: 250 ° C.) to obtain a separator for a lead storage battery. The area per sheet of the lead-acid battery separator was 235 cm ² / sheet.

[Example 2A]
Sheet A and sheet B1 were adhered with an adhesive (positional displacement preventing means) to obtain a separator for a lead storage battery. As the sheet A and the sheet B1, the same sheets as in Example 1A were used. The constituent material of the adhesive was atactic polypropylene. The bonding position was the same as in Example 1A. The adhesive area was 10 cm ² / sheet.

[Example 3A]
Sheet A and sheet B1 were adhered with double-sided tape (positional displacement preventing means) to obtain a separator for a lead storage battery. As the double-sided tape, a tape having a base material of paper and an adhesive of atactic polypropylene was used. The bonding position was the same as in Example 1A. As the double-sided tape, a double-sided tape for general work manufactured by ASKUL Corporation was used. The width of the double-sided tape was 10 mm.

[Example 4A]
Sheet A and sheet B1 were adhered by crimping (positional displacement preventing means) to obtain a separator for a lead storage battery. The crimping was performed by sandwiching the sheet A and the sheet B1 with a metal gear and rotating the gear. The bonding position was the same as in Example 1A.

[Comparative Example 1]
Sheet A and a porous sheet having an average pore diameter of 40 μm (polypropylene non-woven fabric; hereinafter referred to as “sheet B2”; double-sided sulfonate treatment, width: 100 mm, thickness: 0.1 mm) without using misalignment prevention means. Was superposed to obtain a separator for a lead storage battery.

[Example 5A]
Sheet A and sheet B1 were welded by ultrasonic welding (positional displacement preventing means) to obtain a separator for a lead storage battery. Ultrasonic welding was performed under the following conditions. As the sheet A and the sheet B1, the same sheets as in Example 1A were used. The arrangement position of the ultrasonic welding portion was the same as in Example 1A.
{Ultrasonic welding conditions}
(1) Energy: 330J
(2) Output power: 30W
(3) Oscillation frequency: 39.5 kHz
(4) Output amplitude: 80% (80% of the amplitude determined by the settings (1) to (3) above)
(5) Distance between horn and welded part: 0.15 mm

[Example 6A]
Instead of sheet B1, a polypropylene porous sheet whose surface (both sides) is treated with fluorine gas (hereinafter referred to as "sheet B3". "Non-woven fabric" manufactured by Japan Vilene Co., Ltd. Width: 100 mm, thickness: 0. A separator for a lead storage battery was obtained in the same manner as in Example 1A except that 1 mm, average pore diameter: 40 μm, and grain: 40 g / m ² ) were used. Since the surface of the sheet B3 is treated with fluorine gas, it has a sulfone group, a carboxyl group and a hydroxyl group. The same applies to the following fluorine gas treatment.

[Example 7A]
Instead of sheet B1, a non-woven fabric (porous sheet. Mixed fiber containing pulp, glass fiber and silica powder, which is composed of mixed fibers whose surfaces (both sides) are treated with fluorine gas. Hereinafter, the width is referred to as "sheet B4". A separator for a lead storage battery was obtained in the same manner as in Example 2A except that (100 mm, thickness: 0.1 mm, average pore diameter: 1 μm) was used.

[Example 8A]
A separator for a lead storage battery was obtained in the same manner as in Example 7A except that a non-woven fabric having a width of the sheet B4 changed to 97 mm (hereinafter referred to as “sheet B5”) was used instead of the sheet B4.

[Example 9A]
A separator for a lead storage battery was obtained in the same manner as in Example 7A except that a non-woven fabric having a width of the sheet B4 changed to 111 mm (hereinafter referred to as “sheet B6”) was used instead of the sheet B4.

[Example 10A]
Example 7A except that the formation position of the misalignment prevention portion is changed to a position of 15.5 mm from both ends on the long side of the sheet B4 (a position of 23 mm from both ends on the long side of the sheet A). In the same manner as above, a separator for a lead storage battery was obtained.

[Example 11A]
A separator for a lead storage battery was obtained in the same manner as in Example 7A except that a non-woven fabric having a width of the sheet B4 changed to 113 mm (hereinafter referred to as “sheet B7”) was used instead of the sheet B4.

[Example 12A]
A separator for a lead storage battery was obtained in the same manner as in Example 7A except that a non-woven fabric having a width of the sheet B4 changed to 95 mm (hereinafter referred to as “sheet B8”) was used instead of the sheet B4.

[Example 13A]
Instead of the sheet B1, a porous sheet made of glass fiber without surface treatment (hereinafter referred to as "sheet B9"; width: 100 mm, thickness: 0.1 mm, average pore diameter: 1 μm) was used. A separator for a lead storage battery was obtained in the same manner as in Example 2A except for the above.

(Position deviation evaluation)
As shown in FIG. 4, a metal gear is used to form a mechanical seal on the lead-acid battery separators (micropore sheets with perforated sheets) of Examples 1A to 13A and Comparative Example 1 to form a negative electrode storage bag for lead-acid batteries. The presence or absence of misalignment of the sheets A and B1 to B9 at the time of production was evaluated. The non-woven fabric was adjusted to be located inside the negative electrode storage bag. The number (n number) of prepared negative electrode storage bags for lead-acid batteries was 100 in each of Examples 1A to 13A and Comparative Example 1. The presence or absence of misalignment was visually determined. The results are shown in Tables 1 and 2 below.

As is clear from Tables 1 and 2, in Examples 1A to 13A, there was no occurrence of misalignment by using the misalignment prevention means, but in Comparative Example 1, misalignment occurred as much as 23%. did. It is considered that this is because the means for preventing the misalignment between the sheet A and the sheets B1 to B9 is not provided.

<Test B: Evaluation of battery performance>
(Making separators for lead-acid batteries)
[Example 1B]
A separator for a lead storage battery was obtained in the same manner as in Example 1A.

[Example 2B]
A separator for a lead storage battery was obtained in the same manner as in Example 1A except that the sheet B2 was used as the perforated sheet.

[Example 3B]
Example 1A except that a porous sheet having an average pore diameter of 80 μm (polypropylene non-woven fabric; hereinafter referred to as “sheet B10”; double-sided sulfonate treatment, width: 100 mm, thickness: 0.1 mm) was used as the porous sheet. Similarly, a separator for a lead storage battery was obtained.

[Example 4B]
Example 1A and Example 1A except that a porous sheet having an average pore diameter of 100 μm (polypropylene non-woven fabric; hereinafter referred to as “sheet B11”; double-sided sulfonate treatment, width: 100 mm, thickness: 0.1 mm) was used as the porous sheet. Similarly, a separator for a lead storage battery was obtained.

[Example 5B]
Example 1A and Example 1A except that a porous sheet having an average pore diameter of 200 μm (polypropylene non-woven fabric; hereinafter referred to as “sheet B12”; double-sided sulfonate treatment, width: 100 mm, thickness: 0.1 mm) was used as the porous sheet. Similarly, a separator for a lead storage battery was obtained.

[Example 6B]
A negative electrode storage bag (bag-shaped double separator) for a lead storage battery that did not shift in position in Comparative Example 1 was prepared.

[Example 7B]
As the porous sheet, the same as in Example 1A except that a porous sheet having an average pore diameter of 40 μm (polypropylene non-woven fabric; hereinafter referred to as “sheet B13”; double-sided fluorine gas treatment, width: 100 mm, thickness: 0.1 mm) was used. Similarly, a separator for a lead storage battery was obtained.

[Example 8B]
A separator for a lead storage battery was obtained in the same manner as in Example 8A.

[Example 9B]
A separator for a lead storage battery was obtained in the same manner as in Example 12A.

[Example 10B]
A separator for a lead storage battery was obtained in the same manner as in Example 7A.

[Example 11B]
A separator for a lead storage battery was obtained in the same manner as in Example 7A except that the width of the misalignment prevention portion was changed to 0.4 mm.

[Example 12B]
A separator for a lead storage battery was obtained in the same manner as in Example 7A except that the width of the misalignment prevention portion was changed to 1.5 mm.

[Example 13B]
A separator for a lead storage battery was obtained in the same manner as in Example 7A except that the width of the misalignment prevention portion was changed to 1.6 mm.

[Example 14B]
A separator for a lead storage battery was obtained in the same manner as in Example 2A except that the sheet B9 was used as the perforated sheet.

[Reference example 1]
A negative electrode storage bag (bag-shaped double separator) for a lead storage battery misaligned in Comparative Example 1 was prepared.

(Making lead-acid batteries)
[Preparation of positive electrode plate]
Lead powder and lead tan (Pb ₃ O ₄ ) were used as raw materials for the positive electrode active material (lead powder: lead tan = 90: 3.9 (mass ratio)). The raw material of the positive electrode active material, 0.07% by mass of short reinforcing fibers (acrylic fibers) based on the total mass of the raw material of the positive electrode active material, and water were mixed and kneaded. Subsequently, dilute sulfuric acid (specific gravity 1.280) was added little by little and kneaded to prepare a positive electrode material paste. This positive electrode material paste was filled in an expanding type current collector produced by subjecting a rolled sheet made of a lead alloy to an expanding process. Next, the current collector filled with the positive electrode material paste was aged for 24 hours in an atmosphere having a temperature of 50 ° C. and a humidity of 98%. Then, it was dried to prepare an unchemical positive electrode plate.

[Manufacturing of negative electrode plate]
Lead powder was used as a raw material for the negative electrode active material. Bispers P215 (a condensate of a bisphenol compound, aminobenzenesulfonic acid and formaldehyde, manufactured by Nippon Paper Co., Ltd., trade name) was 0.2% by mass (solid content equivalent), and short reinforcing fibers (acrylic fibers) were 0. A mixture containing 1% by mass, 1.0% by mass of barium sulfate, and 2% by mass of a carbon material (scaly graphite (particle size 180 μm)) was added to the lead powder and then dry-mixed (the blending amount is the negative electrode activity). The blending amount is based on the total mass of the raw material of the substance). Next, water was added and then kneaded. Subsequently, dilute sulfuric acid (specific gravity 1.280) was added little by little and kneaded to prepare a negative electrode material paste. This negative electrode material paste was filled in an expanding type current collector produced by subjecting a rolled sheet made of a lead alloy to an expanding process. Next, the current collector filled with the negative electrode material paste was aged for 24 hours in an atmosphere having a temperature of 50 ° C. and a humidity of 98%. Then, it was dried to prepare an unchemical negative electrode plate.

[Battery assembly]
After making a crease in the longitudinal direction in the center of the longitudinal direction of the separators for lead storage batteries of Examples 1B to 5B and 7B to 14B and bending them into a U-shaped cross section, the unchemical negative electrode plate is formed inside the space having a U-shaped cross section. Placed in. Then, both side portions adjacent to the bent portion were sealed with mechanical seals to obtain a bag-shaped double separator (inside: non-woven fabric, outside: polyethylene separator). The non-woven fabric was adjusted to be located inside the negative electrode storage bag. Subsequently, the unchemical negative electrode plate was housed in the bag-shaped double separators of Examples 1B to 14B and Reference Example 1. Further, 6 unchemicald negative electrode plates in a bag-shaped double separator and 5 unchemicald positive electrode plates were alternately laminated.

Subsequently, the ears of the plates having the same polarity were welded to each other by a cast-on-strap (COS) method to prepare a group of plates. A 2V single cell battery (corresponding to a B19 size single cell specified in JIS D 5301) was assembled by inserting the electrode plate group into the battery case. Dilute sulfuric acid having a specific gravity of 1.210 in which sodium sulfate was dissolved was injected into this battery so that the sodium ion concentration contained in the finished electrolytic solution (dilute sulfuric acid) after chemical conversion was 0.1 mol / L. Then, a lead storage battery was obtained by chemical conversion in a water tank at 40 ° C. under the condition of a current of 10 A for 20 hours. The specific gravity of the electrolytic solution after chemical conversion was 1.280 (20 ° C. conversion). In Reference Example 1, it could not be formed and a lead storage battery could not be obtained.

(Evaluation of battery performance)
For these lead-acid batteries, the charge acceptance performance, 5-hour rate capacity, discharge characteristics, stratification suppressing effect, and number of life cycles were evaluated. The results are shown in Tables 3 and 4 below. The measurement method of each measurement is shown below.

[Charge acceptance performance]
After adjusting the SOC (charged state) of the lead-acid battery at the initial stage of assembly to 90% of the fully charged state in a constant temperature bath at 25 ° C., applying a charging voltage of 2.33 V (however, before reaching 2.33 V) The charging current value (5th second charging current value) was measured 5 seconds after the start (current is limited to 100A). The higher the charge current value at the 5th second, the higher the initial charge acceptance performance. The charge acceptance performance was relatively evaluated with the measurement result of Example 1B as 100.

[5-hour rate capacity]
In the produced battery, a constant current was discharged at 25 ° C. and 6 A, and a 5-hour rate capacity was calculated based on the discharge duration until the cell voltage fell below 1.75 V. The 5-hour rate capacity was relatively evaluated with the measurement result of Example 1B as 100.

[Discharge characteristics]
As a discharge characteristic, constant current discharge was performed at 5 C at −15 ° C., and the discharge duration until the battery voltage reached 1.0 V was measured. The longer the discharge duration, the better the discharge characteristics of the battery. The C is a relative representation of the magnitude of the current when the rated capacity is constantly discharged from the fully charged state. For example, the current capable of discharging the rated capacity in 1 hour is expressed as "1C", and the current capable of discharging the rated capacity in 2 hours is expressed as "0.5C". The discharge characteristics were relatively evaluated with the measurement result of Example 1B as 100.

[Effect of suppressing stratification and number of life cycles]
While maintaining the lead storage battery in an atmosphere of 25 ° C., (i) discharge at a discharge current of 45 A for 59 seconds, (ii) discharge at a discharge current of 300 A for 1 second, (iii) constant current at a charging voltage of 2.33 V (limit current 100 A). A cycle test in which constant voltage charging (i) to (iii) was set as one cycle was repeated 3600 times (Battery Industry Association Standard: SBAS0101). The specific gravity of the upper part and the lower part of the electrolytic solution was measured at the 3600th time, and the effect of suppressing stratification was evaluated by the difference in the specific gravity. The smaller the value, the more the stratification can be suppressed. Further, the number of cycles until the battery voltage dropped to 1.2 V after continuing the cycle was evaluated as the number of life cycles.

Focusing on the charge acceptance performance, it can be confirmed that the larger the average pore diameter of the porous sheet, the better the charge acceptance performance. It is considered that this is because the average pore diameter of the porous sheet is large, so that the movement of sulfate ions is not easily inhibited. Focusing on the effect of suppressing stratification, it can be confirmed that the smaller the average pore diameter of the porous sheet, the better the effect of suppressing stratification. It is considered that this is because the small average pore diameter of the porous sheet improves the performance of retaining sulfate ions. Focusing on the number of life cycles, it can be confirmed that the higher the effect of suppressing stratification, the larger the number of life cycles. As a result of evaluating the number of life cycles after producing a lead-acid battery in the same manner as in Example 1B using the separators for lead-acid batteries of Examples 2A to 6A, 9A to 11A, and 13A, the evaluation result equivalent to that of Example 1B was obtained. Obtained.

10 ... positive electrode, 20 ... negative electrode, 30 ... separator (separator for lead storage battery), 32 ... mechanical seal part, 40, 50 ... porous sheet, 40a, 50a ... one side, 40b, 50b ... other side, 41 ... base part, 42 ... Ribs, 43 ... Mini ribs, 60 ... Laminated sheets, 70 ... Misalignment prevention part, A ... Rib bottom width, B ... Rib top bottom width, H ... Rib height, T1 ... Base thickness, T2 ... Thickness of the porous sheet.

Claims (11)

A long first porous sheet and a laminated sheet having a second porous sheet laminated on the first porous sheet, and
A misalignment prevention unit that fixes the relative positions of the first perforated sheet and the second perforated sheet, and
A mechanical seal portion for forming the laminated sheet into a bag shape is provided.
A plurality of the misalignment prevention portions are arranged along the longitudinal direction of the first porous sheet together with being an adhesive.
The edge of the first porous sheet on the surface of the first porous sheet on the side of the second porous sheet, which is present on at least one of the sides of the first porous sheet in the lateral direction, is exposed from the second porous sheet.
The laminated sheet is formed in a bag shape by joining the edges of the first porous sheet to each other by the mechanical seal portion.
The shortest distance from the end of the first porous sheet to the end of the misalignment prevention portion in the lateral direction of the first porous sheet is larger than the exposure amount of the first porous sheet in the lateral direction. , Separator for lead-acid batteries. The separator for a lead storage battery according to claim 1, wherein the first porous sheet and the second porous sheet are in contact with each other. The separator for a lead storage battery according to claim 1 or 2, wherein the average pore diameter of the second porous sheet is 1 to 200 μm. The separator for a lead storage battery according to any one of claims 1 to 3, wherein the second porous sheet contains at least one selected from the group consisting of organic fibers, glass fibers and pulp. The separator for a lead storage battery according to any one of claims 1 to 4, wherein at least one surface of the second porous sheet is hydrophilized. The lead-acid battery according to any one of claims 1 to 5, wherein the edge portion of the first porous sheet has a portion where the exposure amount in the lateral direction of the first porous sheet is 2 to 9 mm. Separator for. The separator for a lead storage battery according to any one of claims 1 to 6, wherein at least one surface of the second porous sheet has at least one selected from the group consisting of a sulfone group, a carboxyl group and a hydroxyl group. The laminated sheet is bent so that the second porous sheet is located inside, and the edges of the first porous sheet are joined to each other to form a space in which the electrodes can be stored. , The separator for a lead storage battery according to any one of claims 1 to 7 . The method for manufacturing a separator for a lead storage battery according to any one of claims 1 to 8 .
For lead-acid batteries, comprising a step of laminating the first porous sheet and the second porous sheet to obtain a separator so that the edge portion of the first porous sheet is exposed from the second porous sheet. Manufacturing method of separator. The lead-acid battery separator according to claim 8 , a positive electrode, and a negative electrode housed in the space of the separator are provided.
A lead-acid battery in which the negative electrode and the positive electrode are alternately arranged. The method for manufacturing a lead-acid battery according to claim 10 .
A method for manufacturing a lead-acid battery, comprising a step of obtaining a lead-acid battery using the positive electrode, the negative electrode, and the separator.

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